[PATCH v1 0/6] kselftest/arm64: SVE signal handling tests

[PATCH v1 0/6] kselftest/arm64: SVE signal handling tests

[Mark Brown]

Currently we have no real tests for SVE signal handling (though the
stress test does trigger the code paths as it regularly sends signals to
the test processes).  Add some basic coverage, this is very much
incomplete but it's more coverage than we currently have, a TODO file is
included with some omissions that occurred to me.

Mark Brown (6):
  kselftest/arm64: signal: Add SVE to the set of features we can check
    for
  kselftest/arm64: signal: Support signal frames with SVE register data
  kselftest/arm64: signal: Check SVE signal frame shows expected vector
    length
  kselftest/arm64: signal: Verify that signals can't change the SVE
    vector length
  kselftest/arm64: signal: Add test case for SVE register state in
    signals
  kselftest/arm64: signal: Add a TODO list for signal handling tests

 .../testing/selftests/arm64/signal/.gitignore |   1 +
 .../selftests/arm64/signal/test_signals.h     |   2 +
 .../arm64/signal/test_signals_utils.c         |   3 +
 .../selftests/arm64/signal/testcases/TODO     |   2 +
 .../testcases/fake_sigreturn_sve_change_vl.c  |  92 +++++++++++++
 .../arm64/signal/testcases/sve_regs.c         | 126 ++++++++++++++++++
 .../selftests/arm64/signal/testcases/sve_vl.c |  68 ++++++++++
 .../arm64/signal/testcases/testcases.c        |  34 ++++-
 8 files changed, 325 insertions(+), 3 deletions(-)
 create mode 100644 tools/testing/selftests/arm64/signal/testcases/TODO
 create mode 100644 tools/testing/selftests/arm64/signal/testcases/fake_sigreturn_sve_change_vl.c
 create mode 100644 tools/testing/selftests/arm64/signal/testcases/sve_regs.c
 create mode 100644 tools/testing/selftests/arm64/signal/testcases/sve_vl.c


base-commit: ff1176468d368232b684f75e82563369208bc371
-- 
2.20.1


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[PATCH v1 1/6] kselftest/arm64: signal: Add SVE to the set of features we can check for

[Mark Brown]

Allow testcases for SVE signal handling to flag the dependency and be
skipped on systems without SVE support.

Signed-off-by: Mark Brown <broonie@kernel.org>
---
 tools/testing/selftests/arm64/signal/test_signals.h       | 2 ++
 tools/testing/selftests/arm64/signal/test_signals_utils.c | 3 +++
 2 files changed, 5 insertions(+)

diff --git a/tools/testing/selftests/arm64/signal/test_signals.h b/tools/testing/selftests/arm64/signal/test_signals.h
index f96baf1cef1a..ebe8694dbef0 100644
--- a/tools/testing/selftests/arm64/signal/test_signals.h
+++ b/tools/testing/selftests/arm64/signal/test_signals.h
@@ -33,10 +33,12 @@
  */
 enum {
 	FSSBS_BIT,
+	FSVE_BIT,
 	FMAX_END
 };
 
 #define FEAT_SSBS		(1UL << FSSBS_BIT)
+#define FEAT_SVE		(1UL << FSVE_BIT)
 
 /*
  * A descriptor used to describe and configure a test case.
diff --git a/tools/testing/selftests/arm64/signal/test_signals_utils.c b/tools/testing/selftests/arm64/signal/test_signals_utils.c
index 2de6e5ed5e25..6836510a522f 100644
--- a/tools/testing/selftests/arm64/signal/test_signals_utils.c
+++ b/tools/testing/selftests/arm64/signal/test_signals_utils.c
@@ -26,6 +26,7 @@ static int sig_copyctx = SIGTRAP;
 
 static char const *const feats_names[FMAX_END] = {
 	" SSBS ",
+	" SVE ",
 };
 
 #define MAX_FEATS_SZ	128
@@ -263,6 +264,8 @@ int test_init(struct tdescr *td)
 		 */
 		if (getauxval(AT_HWCAP) & HWCAP_SSBS)
 			td->feats_supported |= FEAT_SSBS;
+		if (getauxval(AT_HWCAP) & HWCAP_SVE)
+			td->feats_supported |= FEAT_SVE;
 		if (feats_ok(td))
 			fprintf(stderr,
 				"Required Features: [%s] supported\n",
-- 
2.20.1


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[PATCH v1 2/6] kselftest/arm64: signal: Support signal frames with SVE register data

[Mark Brown]

A signal frame with SVE may validly either be a bare struct sve_context or
a struct sve_context followed by vector length dependent register data.
Support either in the generic helpers for the signal tests, and while we're
at it validate the SVE vector length reported.

Signed-off-by: Mark Brown <broonie@kernel.org>
---
 .../arm64/signal/testcases/testcases.c        | 34 +++++++++++++++++--
 1 file changed, 31 insertions(+), 3 deletions(-)

diff --git a/tools/testing/selftests/arm64/signal/testcases/testcases.c b/tools/testing/selftests/arm64/signal/testcases/testcases.c
index 61ebcdf63831..8c2a57fc2f9c 100644
--- a/tools/testing/selftests/arm64/signal/testcases/testcases.c
+++ b/tools/testing/selftests/arm64/signal/testcases/testcases.c
@@ -50,12 +50,38 @@ bool validate_extra_context(struct extra_context *extra, char **err)
 	return true;
 }
 
+bool validate_sve_context(struct sve_context *sve, char **err)
+{
+	/* Size will be rounded up to a multiple of 16 bytes */
+	size_t regs_size
+		= ((SVE_SIG_CONTEXT_SIZE(sve_vq_from_vl(sve->vl)) + 15) / 16) * 16;
+
+	if (!sve || !err)
+		return false;
+
+	/* Either a bare sve_context or a sve_context followed by regs data */
+	if ((sve->head.size != sizeof(struct sve_context)) &&
+	    (sve->head.size != regs_size)) {
+		*err = "bad size for SVE context";
+		return false;
+	}
+
+	if (!sve_vl_valid(sve->vl)) {
+		*err = "SVE VL invalid";
+
+		return false;
+	}
+
+	return true;
+}
+
 bool validate_reserved(ucontext_t *uc, size_t resv_sz, char **err)
 {
 	bool terminated = false;
 	size_t offs = 0;
 	int flags = 0;
 	struct extra_context *extra = NULL;
+	struct sve_context *sve = NULL;
 	struct _aarch64_ctx *head =
 		(struct _aarch64_ctx *)uc->uc_mcontext.__reserved;
 
@@ -90,9 +116,8 @@ bool validate_reserved(ucontext_t *uc, size_t resv_sz, char **err)
 		case SVE_MAGIC:
 			if (flags & SVE_CTX)
 				*err = "Multiple SVE_MAGIC";
-			else if (head->size !=
-				 sizeof(struct sve_context))
-				*err = "Bad size for sve_context";
+			/* Size is validated in validate_sve_context() */
+			sve = (struct sve_context *)head;
 			flags |= SVE_CTX;
 			break;
 		case EXTRA_MAGIC:
@@ -137,6 +162,9 @@ bool validate_reserved(ucontext_t *uc, size_t resv_sz, char **err)
 		if (flags & EXTRA_CTX)
 			if (!validate_extra_context(extra, err))
 				return false;
+		if (flags & SVE_CTX)
+			if (!validate_sve_context(sve, err))
+				return false;
 
 		head = GET_RESV_NEXT_HEAD(head);
 	}
-- 
2.20.1


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[PATCH v1 3/6] kselftest/arm64: signal: Check SVE signal frame shows expected vector length

[Mark Brown]

As a basic check that the SVE signal frame is being set up correctly
verify that the vector length in the signal frame is the vector length
that the process has.

Signed-off-by: Mark Brown <broonie@kernel.org>
---
 .../testing/selftests/arm64/signal/.gitignore |  1 +
 .../selftests/arm64/signal/testcases/sve_vl.c | 68 +++++++++++++++++++
 2 files changed, 69 insertions(+)
 create mode 100644 tools/testing/selftests/arm64/signal/testcases/sve_vl.c

diff --git a/tools/testing/selftests/arm64/signal/.gitignore b/tools/testing/selftests/arm64/signal/.gitignore
index 78c902045ca7..c1742755abb9 100644
--- a/tools/testing/selftests/arm64/signal/.gitignore
+++ b/tools/testing/selftests/arm64/signal/.gitignore
@@ -1,4 +1,5 @@
 # SPDX-License-Identifier: GPL-2.0-only
 mangle_*
 fake_sigreturn_*
+sve_*
 !*.[ch]
diff --git a/tools/testing/selftests/arm64/signal/testcases/sve_vl.c b/tools/testing/selftests/arm64/signal/testcases/sve_vl.c
new file mode 100644
index 000000000000..92904653add1
--- /dev/null
+++ b/tools/testing/selftests/arm64/signal/testcases/sve_vl.c
@@ -0,0 +1,68 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Copyright (C) 2021 ARM Limited
+ *
+ * Check that the SVE vector length reported in signal contexts is the
+ * expected one.
+ */
+
+#include <signal.h>
+#include <ucontext.h>
+#include <sys/prctl.h>
+
+#include "test_signals_utils.h"
+#include "testcases.h"
+
+struct fake_sigframe sf;
+unsigned int vl;
+
+static bool get_sve_vl(struct tdescr *td)
+{
+	int ret = prctl(PR_SVE_GET_VL);
+	if (ret == -1)
+		return false;
+
+	vl = ret;
+
+	return true;
+}
+
+static int sve_vl(struct tdescr *td, siginfo_t *si, ucontext_t *uc)
+{
+	size_t resv_sz, offset;
+	struct _aarch64_ctx *head = GET_SF_RESV_HEAD(sf);
+	struct sve_context *sve;
+
+	/* Get a signal context which should have a SVE frame in it */
+	if (!get_current_context(td, &sf.uc))
+		return 1;
+
+	resv_sz = GET_SF_RESV_SIZE(sf);
+	head = get_header(head, SVE_MAGIC, resv_sz, &offset);
+	if (!head) {
+		fprintf(stderr, "No SVE context\n");
+		return 1;
+	}
+	sve = (struct sve_context *)head;
+
+	if (sve->vl != vl) {
+		fprintf(stderr, "sigframe VL %u, expected %u\n",
+			sve->vl, vl);
+		return 1;
+	} else {
+		fprintf(stderr, "got expected VL %u\n", vl);
+	}
+
+	td->pass = 1;
+
+	return 0;
+}
+
+struct tdescr tde = {
+	.name = "SVE VL",
+	.descr = "Check that we get the right SVE VL reported",
+	.feats_required = FEAT_SVE,
+	.timeout = 3,
+	.init = get_sve_vl,
+	.run = sve_vl,
+};
-- 
2.20.1


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[PATCH v1 4/6] kselftest/arm64: signal: Verify that signals can't change the SVE vector length

[Mark Brown]

We do not support changing the SVE vector length as part of signal return,
verify that this is the case if the system supports multiple vector lengths.

Signed-off-by: Mark Brown <broonie@kernel.org>
---
 .../testcases/fake_sigreturn_sve_change_vl.c  | 92 +++++++++++++++++++
 1 file changed, 92 insertions(+)
 create mode 100644 tools/testing/selftests/arm64/signal/testcases/fake_sigreturn_sve_change_vl.c

diff --git a/tools/testing/selftests/arm64/signal/testcases/fake_sigreturn_sve_change_vl.c b/tools/testing/selftests/arm64/signal/testcases/fake_sigreturn_sve_change_vl.c
new file mode 100644
index 000000000000..bb50b5adbf10
--- /dev/null
+++ b/tools/testing/selftests/arm64/signal/testcases/fake_sigreturn_sve_change_vl.c
@@ -0,0 +1,92 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Copyright (C) 2021 ARM Limited
+ *
+ * Attempt to change the SVE vector length in a signal hander, this is not
+ * supported and is expected to segfault.
+ */
+
+#include <signal.h>
+#include <ucontext.h>
+#include <sys/prctl.h>
+
+#include "test_signals_utils.h"
+#include "testcases.h"
+
+struct fake_sigframe sf;
+static unsigned int vls[SVE_VQ_MAX];
+unsigned int nvls = 0;
+
+static bool sve_get_vls(struct tdescr *td)
+{
+	int vq, vl;
+
+	/*
+	 * Enumerate up to SVE_VQ_MAX vector lengths
+	 */
+	for (vq = SVE_VQ_MAX; vq > 0; --vq) {
+		vl = prctl(PR_SVE_SET_VL, vq * 16);
+		if (vl == -1)
+			return false;
+
+		vl &= PR_SVE_VL_LEN_MASK;
+
+		/* Skip missing VLs */
+		vq = sve_vq_from_vl(vl);
+
+		vls[nvls++] = vl;
+	}
+
+	/* We need at least two VLs */
+	if (nvls < 2) {
+		fprintf(stderr, "Only %d VL supported\n", nvls);
+		return false;
+	}
+
+	return true;
+}
+
+static int fake_sigreturn_sve_change_vl(struct tdescr *td,
+					siginfo_t *si, ucontext_t *uc)
+{
+	size_t resv_sz, offset;
+	struct _aarch64_ctx *head = GET_SF_RESV_HEAD(sf);
+	struct sve_context *sve;
+
+	/* Get a signal context with a SVE frame in it */
+	if (!get_current_context(td, &sf.uc))
+		return 1;
+
+	resv_sz = GET_SF_RESV_SIZE(sf);
+	head = get_header(head, SVE_MAGIC, resv_sz, &offset);
+	if (!head) {
+		fprintf(stderr, "No SVE context\n");
+		return 1;
+	}
+
+	if (head->size != sizeof(struct sve_context)) {
+		fprintf(stderr, "SVE register state active, skipping\n");
+		return 1;
+	}
+
+	sve = (struct sve_context *)head;
+
+	/* No changes are supported; init left us at minimum VL so go to max */
+	fprintf(stderr, "Attempting to change VL from %d to %d\n",
+		sve->vl, vls[0]);
+	sve->vl = vls[0];
+
+	fake_sigreturn(&sf, sizeof(sf), 0);
+
+	return 1;
+}
+
+struct tdescr tde = {
+	.name = "FAKE_SIGRETURN_SVE_CHANGE",
+	.descr = "Attempt to change SVE VL",
+	.feats_required = FEAT_SVE,
+	.sig_ok = SIGSEGV,
+	.timeout = 3,
+	.init = sve_get_vls,
+	.run = fake_sigreturn_sve_change_vl,
+};
-- 
2.20.1


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[PATCH v1 5/6] kselftest/arm64: signal: Add test case for SVE register state in signals

[Mark Brown]

Currently this doesn't actually verify that the register contents do the
right thing, it just verifes that a SVE context with appropriate size
appears.

Signed-off-by: Mark Brown <broonie@kernel.org>
---
 .../arm64/signal/testcases/sve_regs.c         | 126 ++++++++++++++++++
 1 file changed, 126 insertions(+)
 create mode 100644 tools/testing/selftests/arm64/signal/testcases/sve_regs.c

diff --git a/tools/testing/selftests/arm64/signal/testcases/sve_regs.c b/tools/testing/selftests/arm64/signal/testcases/sve_regs.c
new file mode 100644
index 000000000000..4b2418aa08a9
--- /dev/null
+++ b/tools/testing/selftests/arm64/signal/testcases/sve_regs.c
@@ -0,0 +1,126 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Copyright (C) 2021 ARM Limited
+ *
+ * Verify that the SVE register context in signal frames is set up as
+ * expected.
+ */
+
+#include <signal.h>
+#include <ucontext.h>
+#include <sys/prctl.h>
+
+#include "test_signals_utils.h"
+#include "testcases.h"
+
+struct fake_sigframe sf;
+static unsigned int vls[SVE_VQ_MAX];
+unsigned int nvls = 0;
+
+static bool sve_get_vls(struct tdescr *td)
+{
+	int vq, vl;
+
+	/*
+	 * Enumerate up to SVE_VQ_MAX vector lengths
+	 */
+	for (vq = SVE_VQ_MAX; vq > 0; --vq) {
+		vl = prctl(PR_SVE_SET_VL, vq * 16);
+		if (vl == -1)
+			return false;
+
+		vl &= PR_SVE_VL_LEN_MASK;
+
+		/* Skip missing VLs */
+		vq = sve_vq_from_vl(vl);
+
+		vls[nvls++] = vl;
+	}
+
+	/* We need at least one VL */
+	if (nvls < 1) {
+		fprintf(stderr, "Only %d VL supported\n", nvls);
+		return false;
+	}
+
+	return true;
+}
+
+static void setup_sve_regs(void)
+{
+	/* RDVL x16, #1 so we should have SVE regs; real data is TODO */
+	asm volatile(".inst 0x04bf5030" : : : "x16" );
+}
+
+static int do_one_sve_vl(struct tdescr *td, siginfo_t *si, ucontext_t *uc,
+			 unsigned int vl)
+{
+	size_t resv_sz, offset;
+	struct _aarch64_ctx *head = GET_SF_RESV_HEAD(sf);
+	struct sve_context *sve;
+
+	fprintf(stderr, "Testing VL %d\n", vl);
+
+	if (prctl(PR_SVE_SET_VL, vl) == -1) {
+		fprintf(stderr, "Failed to set VL\n");
+		return 1;
+	}
+
+	/*
+	 * Get a signal context which should have a SVE frame and registers
+	 * in it.
+	 */
+	setup_sve_regs();
+	if (!get_current_context(td, &sf.uc))
+		return 1;
+
+	resv_sz = GET_SF_RESV_SIZE(sf);
+	head = get_header(head, SVE_MAGIC, resv_sz, &offset);
+	if (!head) {
+		fprintf(stderr, "No SVE context\n");
+		return 1;
+	}
+
+	sve = (struct sve_context *)head;
+	if (sve->vl != vl) {
+		fprintf(stderr, "Got VL %d, expected %d\n", sve->vl, vl);
+		return 1;
+	}
+
+	/* The actual size validation is done in get_current_context() */
+	fprintf(stderr, "Got expected size %u and VL %d\n",
+		head->size, sve->vl);
+
+	return 0;
+}
+
+static int sve_regs(struct tdescr *td, siginfo_t *si, ucontext_t *uc)
+{
+	int i;
+
+	for (i = 0; i < nvls; i++) {
+		/*
+		 * TODO: the signal test helpers can't currently cope
+		 * with signal frames bigger than struct sigcontext,
+		 * skip VLs that will trigger that.
+		 */
+		if (vls[i] > 64)
+			continue;
+
+		if (do_one_sve_vl(td, si, uc, vls[i]))
+			return 1;
+	}
+
+	td->pass = 1;
+
+	return 0;
+}
+
+struct tdescr tde = {
+	.name = "SVE registers",
+	.descr = "Check that we get the right SVE registers reported",
+	.feats_required = FEAT_SVE,
+	.timeout = 3,
+	.init = sve_get_vls,
+	.run = sve_regs,
+};
-- 
2.20.1


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[PATCH v1 6/6] kselftest/arm64: signal: Add a TODO list for signal handling tests

[Mark Brown]

Note down a few gaps in our coverage.

Signed-off-by: Mark Brown <broonie@kernel.org>
---
 tools/testing/selftests/arm64/signal/testcases/TODO | 2 ++
 1 file changed, 2 insertions(+)
 create mode 100644 tools/testing/selftests/arm64/signal/testcases/TODO

diff --git a/tools/testing/selftests/arm64/signal/testcases/TODO b/tools/testing/selftests/arm64/signal/testcases/TODO
new file mode 100644
index 000000000000..110ff9fd195d
--- /dev/null
+++ b/tools/testing/selftests/arm64/signal/testcases/TODO
@@ -0,0 +1,2 @@
+- Validate that register contents are saved and restored as expected.
+- Support and validate extra_context.
-- 
2.20.1


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Re: [PATCH v1 0/6] kselftest/arm64: SVE signal handling tests

[Catalin Marinas]

On Thu, 19 Aug 2021 14:42:39 +0100, Mark Brown wrote:
> Currently we have no real tests for SVE signal handling (though the
> stress test does trigger the code paths as it regularly sends signals to
> the test processes).  Add some basic coverage, this is very much
> incomplete but it's more coverage than we currently have, a TODO file is
> included with some omissions that occurred to me.
> 
> Mark Brown (6):
>   kselftest/arm64: signal: Add SVE to the set of features we can check
>     for
>   kselftest/arm64: signal: Support signal frames with SVE register data
>   kselftest/arm64: signal: Check SVE signal frame shows expected vector
>     length
>   kselftest/arm64: signal: Verify that signals can't change the SVE
>     vector length
>   kselftest/arm64: signal: Add test case for SVE register state in
>     signals
>   kselftest/arm64: signal: Add a TODO list for signal handling tests
> 
> [...]

Applied to arm64 (for-next/kselftest), thanks!

[1/6] kselftest/arm64: signal: Add SVE to the set of features we can check for
      https://git.kernel.org/arm64/c/d4e4dc4fab68
[2/6] kselftest/arm64: signal: Support signal frames with SVE register data
      https://git.kernel.org/arm64/c/ace19b1845a5
[3/6] kselftest/arm64: signal: Check SVE signal frame shows expected vector length
      https://git.kernel.org/arm64/c/c1f67a19c12e
[4/6] kselftest/arm64: signal: Verify that signals can't change the SVE vector length
      https://git.kernel.org/arm64/c/d25ac50ce8f7
[5/6] kselftest/arm64: signal: Add test case for SVE register state in signals
      https://git.kernel.org/arm64/c/5262b216f4a9
[6/6] kselftest/arm64: signal: Add a TODO list for signal handling tests
      https://git.kernel.org/arm64/c/fa5ca80db89e

-- 
Catalin


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